func-down-hosts: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/func-down-hosts - from package: func

You may install the required package with command yum install {package}
Error in other languages:
func-down-hosts: bevel nie gevind nie
func-down-hosts: comandă negăsită
func-down-hosts: comando não encontrado
func-down-hosts: commande introuvable
func-down-hosts: command not found
func-down-hosts: käsku ei ole
func-down-hosts: không tìm thấy lệnh
func-down-hosts: komanda nerasta
func-down-hosts: Kommando nicht gefunden.
func-down-hosts: kommandot finns inte
func-down-hosts: komut yok
func-down-hosts: nie znaleziono polecenia
func-down-hosts: níor aimsíodh an t-ordú
func-down-hosts: no se encontró la orden
func-down-hosts: no s'ha trobat l'ordre
func-down-hosts: opdracht niet gevonden
func-down-hosts: parancs nem található
func-down-hosts: perintah tidak ditemukan
func-down-hosts: príkaz nenájdený
func-down-hosts: příkaz nenalezen
func-down-hosts: команда не найдена
func-down-hosts: командата не е открита
func-down-hosts: 命令找不到
func-down-hosts: コマンドが見つかりません